Metal cleaning and antitarnish compositions



United States Patent 3,413,231 METAL CLEANING AND ANTITARNISHCOMPOSITIONS Edwin Ralph Kolodny, Stamford, Martin Grayson, SouthNorwalk, and Robert Lee Myers, Greenwich, Conn., assignors to AmericanCyanamid Company, Stamford, Conn., a corporation of Maine No Drawing.Filed July 23, 1965, Ser. No. 474,517 Claims. (Cl. 252171) ABSTRACT OFTHE DISCLOSURE This invention relates to the provision of compositionsuseful as metal cleaning and antitarnish agents. It relates further tometal surfaces which are coated with a thin layer of an organictrivalent phosphorous compound which imparts tarnish resistance to thesurface of the metal. It relates further to compositions containing aphosphine which is generally water or alcohol soluble, and a water and/or alcoholic solvent therefor, said composition containing an amount ofphosphine which is capable of imparting tarnish resistance to a metalsurface to which it is applied.

Generally stated, the subject matter of the present invention relates toa metal cleaning and tarnish inhibiting composition. More particularly,the invention relates to a metal cleaning and tarnish inhibitingcomposition which contains a trivalent organophosphorous compound.

Metal cleaning compositions are employed to remove tarnish and dirt frommetals, and contain as a basic component an abrasive substance. Inaddition, the composition may also contain soaps and emulsified fattyacids which act to both maintain the abrasive substance in uniformsuspension, as well as aid in the removal of tarnish and dirt. Theabrasive substance is selected relative to the hardness of the metal,utilizing as the criterion of selection, maximum abrasion withoutdeleterious scratching of the metal surface. Among the various abrasivesubstances used, either alone or in combination are chalk, collodialclay, diatomite, magnesium oxide, pumice, red iron oxide and the like.Metal cleaning therefore, constitutes an abrading action, and eventhough the abrasive substance is chosen relative to the hardness of themetal there is a gradual diminution of the metal as a consequence to theabrading action.

With regard to tarnish inhibition, effective inhibiting has for the mostpart, with minor exceptions, been nonexistent. The expedient usuallyresorted to requires the use of an oil, such as pine oil or oleic acid,the oil leaving a thin film on the metal surface to act as a protectiveagainst tarnishing. Recently, particular mercaptans have been used astarnish inhibitors for silver; however, an effective silver cleaning andtarnish inhibiting composition still requires the use of an abrasivesubstance along with the mercaptan.

Attempts to obviate the inherent disadvantages of the traditionalabrading metal cleaning compositions resulted in the development of theelectrolytic and chemical processes for cleaning metals; however, as aconsequence to the inherent disadvantages of both processes they havenot been broadly adopted in either industrial, or consumer metalcleaning. The electrolytic process in many instances, results in theremoval of metal to the extent of several thousandths of an inch, andrequires the use of materials such as concentrated sulfuric acid andcyanide, among others. Whereas, the chemical process requires the use ofa composition comprising an acid, having a pH in the range of 1 to 5,and thiourea. Furthermore, the process requires the addition of water tothe aforementioned composition prior to its use; the amount being3,413,231 Patented Nov. 26, 1968 'ice directly dependent on thecharacter of the impurities to be removed from the metal surface.Lastly, effective cleaning necessitates immersion of the article to becleaned in the aforementioned aqueous solution.

The present invention represents the culmination of a series ofinvestigations conducted largely by the inventors and their associatesin the problems of metal cleaning, utilizing purely chemical means andattempting to obviate the inherent disadvantages of the traditionalabrading metal cleaning composition. The inventive concept upon whichthe present invention is based resides in the discovery that trivalentorganophosphorous compounds are effective metal cleaners, in thattarnish and dirt are removed from a metal surface without the inherentdisadvantages of the traditional abrading metal cleaning compositions,and the aforementioned chemical process.

Furthermore, the inventive concept resides in the added discovery thatthe trivalent organophosphorous compounds are capable of effectivelyinhibiting the tarnishing of metal. This unexpected result is presumablydue to the residual bonding of the trivalent phosphorous moities to themetal surface in the form of a tightly adherent, transparent barrierfilm.

Therefore, the invention relates to a metal cleaning and tarnishinhibiting composition comprising a suitable carrier having admixedtherein at least 0.1% by weight of a member selected from the groupconsisting of a water soluble trivalent organophosphorous compound, analcohol soluble trivalent organophosphorous compound and mixturesthereof.

The advantages which inure to the art as a consequence to the advent ofthe present invention should be readily apparent from the foregoing.Primarily, the disadvantage of gradual diminution of the metal as aconsequence to the traditional abrading action of metal cleaning hasbeen obviated. Furthermore, effective tarnish inhibition can be achievedby a tightly adherent, transparent barrier film formed on the metalsurface, said film not materially impairing the brilliance of a cleanedmetal surface.

The following compounds are typical of the trivalent organophosphorouscompounds of the present invention:

(3-hydroxypropyl) phosphine,

[2- (ethoxycarbonyl ethyl] phosphine,

[3- (trimethylammonium) propyl] phosphine chloride,

disodium bis Z-carboxyethyl phosphine,

bis 3-hydroxypropyl phosphine,

bis (3-sulfamoylpropyl) phosphine,

tris (hydroxymethyl phosphine,

tris 3-hydroxypropyl) phosphine,

disodium bis 3-carboxypr0pyl ethylphosphine,

tris (Z-hydroxyethoxymethyl phosphine,

tris( l-hydroxyethyl) phosphine,

tris( l-hydroxy l-me thylethyl) phosphine,

hexyl bis (hydroxymethyl phosphine,

(3-aminopropyl bis 3-hydroxypropyl) phosphine,

s odium dimethyl (3 -sulfopropyl phosphine,

( 3 S-dihydroxyphenyl bis (hydroxymethyl phosphine,

trisodium tris p-carboxy-phenyl phosphine,

tris (2-carbamoylethyl) phosphine,

tris (2,3 -dihydroxypropyl phosphine,

2-hydroxyethyl dipropylphosphinite,

ethyl dimethylphosphinathioite,N-2-hydroxyethyl-p,p-diisobutylphosphinous amide,

p,p-bis Z-hydroxyethyl) -N,N-dimethylphosphinous amide,

dimethyl( 3-hydroxypropyl) phosphonite,

bis (2-hydroxyethyl) [2- (ethoxycarbonyl) ethyl] phosphonite,

bis (p-hydroxyb enzyl methylphosphonodithioite,

p-isobutyl-N,N,N',N-tetramethylphosphonous diamide,

(Z-hydroxyethyl) dimorpholinophosphine,

triethyl phosphite,

trimethyl phosphorotrithioite,

tris 2-hydroxyethyl pho sphite,

hexamethylphosphorous triamide,

hexakis(2-hydroxyethyl) phosphorous triamide,

ethyl N -(2-hydroxyethyl)-p-methylphosphonamidite,

methyl p-ethyl-N,N-dimethylphosphonamidothioite,

diethyl morpholinophosphonite,

dimethyl dimethylphosphoramidodithioite,

2-(2-hydroxyethoxy)ethyl N,N-(2-hydr-oxyethyl) phosphorodiarnidite,

trimethylenebis [bis (hydroxymethyl) phosphine] tetrasodium ethylene-bis[bis(Z-carboxyethyl) phosphine] p-phenylenebis [bis (hydroxymethylphosphine] bis 2-hydroxyethyl) trimethylenebis [ethylphosphinite]ethylene tetrakis (2-hydroxyethyl diphosphite,

oxydiethylene tetraisobutyldiphosphinite,

ethylene 2-hydroxyethyl phosphite,

l-(hydroxymethyl)phosphorinane,

5- (hydroxymethyl) 2-,4,6-triisopropyl-1,3 ,5

dioxaphosphorinane.

Generally, the trivalent organophosphorous compounds utilized in thenovel composition of the present invention have the facility to act as ametal cleaner, as well as a tarnish inhibitor; however, the efliciency fthe compounds, as either a metal cleaner or tarnish inhibitor, isdirectly related to the number, and nature of substituents. For example,a primary phosphine is an effective metal cleaner; however, greatermetal cleaning efiiciency is achieved by utilizing the tertiaryphosphine.

With regard to the nature of the substituents, it has been observed thathere again the nature, that is molecular weight, extent of hydrocarboncharacter, as well as the hydrophilic nature of the substituents, isdirectly related to the efficiency of the compound as either a metalcleaner or tarnish inhibitor. For example, a tertiary phosphine havingsubstituents containing 1 to 8 carbon atoms, as well as watersolubilizing groups, possesses greater efficiency as a metal cleanerthan a tertiary phosphine of hydrocarbon character containingsubstituents of 12 to 20 carbon atoms. Whereas, a tertiary phosphine ofhydrocarbon character containing substituents of 12 to 20 carbon atomspossesses greater efiiciency as a tarnish inhibitor. Therefore, it isconceivable that a metal cleaning and tarnish inhibiting composition ofthe present invention would contain more than one trivalentorganophosphorous compound.

The trivalent organophosphorous compounds utilized in the novelcompositions of the present invention should possess either water oralcohol solubility. It is preferred to use as an alcoholic solvent alower alkyl alcohol, that is an alcohol containing 1 to carbon atoms. Notheory is offered as to the mechanism of activity of the trivalentorganophosphorous compounds of the present invention, nor is it intendedthat the present invention be so limited to any theoreticalconsiderations of the mechanism of activity.

With regard to the concentration of trivalent organophosphorouscompounds present in the novel composition of the present invention,0.1% represents a concentration at which the trivalent organophosphorouscompounds will act both as a metal cleaner, as well as a tarnishinhibitor; however, the efficiency of the trivalent organophosphorouscompounds as metal cleaners is directly related to concentration. Thefactors of concentration and time, that is the time required toaccomplish effective removal of tarnish and dirt from a metal surface,are indirectly proportional, in that as the concentration increases thetime necessary to effectively remove the tarnish and dirt from a metalsurface decreases. However, a point is reached at which an increase inconcentration will not appreciably effect the factor of time. Forexample, the trivalent organophosphorous compounds are effective asmetal cleaners in a pure state, that is 100%, and when so used thedecrease in time is not significant when contrasted to a concentrationof Concerning the effect of concentration on tarnish inhibition, theefficiency of the trivalent organophosphorous compounds is notappreciably effected by concentration, since only a monomolecular layeris necessary to achieve effective tarnish inhibition. Therefore, apreferred concentration which will satisfactorily achieve effectivemetal cleaning, as well as tarnish inhibition is from about 5% to 20%.

The novel composition of the present invention is operable at conditionsof normal room temperature, pressure and humidity, as well as eitheracidic or alkaline conditions. However, the presence of moisture, aswell as conditions of temperature and pH are directly related to thecfficiency of the compounds. With regard to the presence of moisture andtemperature, the efficiency is directly proportional to same, since anincrease in either temperature, or the amount of water present increasesthe efficiency of the compounds. Lastly, the preferred pH may be definedas the ambient pH of the particular trivalent organophosphorous compoundutilized, that is the pH of the solution, either aqueous or alcoholic,in which the compound is dissolved. Since the trivalentorganophosphorous compounds tend to have an ambient pH which is usuallyalkaline, the preferred pH would in most instances be alkaline. However,this should not be construed as a limitation to the invention, since thecompounds are operable in an acidic environment. For example, an aqueoussolution of the compound tris(hydroxymethyl)phosphine, has a pH of 8,which is the preferred pH at which maximum efficiency is achieved,however, the compound is operable at both a higher and lower pH.

As presently used the term suitable carrier may be defined to mean thatcarrier which is compatible with the trivalent organophosphorouscompounds of the present invention, as Well as with the ultimate end useof the composition, that is the metal to which the composition is to beapplied. In addition, the carrier may constitute the solvent in whichthe trivalent organophosphorous compound is dissolved.

Since the trivalent organophosphorous compounds are readily oxidized, itis preferred to formulate the novel metal cleaning and tarnishinhibiting composition of the present invention with an inert propellantunder pressure, to be dispensed as an aerosol foam, cream or the like.The novel composition of the present invention may also include anantioxidant to stabilize the composition such as hydroquinone,monoethylether of hydroquinone, 2,2ditertiarybutyl-4-methylene-6,6'-dimethyl bisphenol, sulfites andbisulfites among others. Furthermore, additional buffing and polishingagents may be added to the novel composition of the present invention,an well as a silver tarnish inhibiting mercaptan, or thioglycolate.Lastly, the composition may also include reducing agents, which aid inthe cleaning of a metal surface such as sodium hydrophosphite, sodiumhyposulfite, hydrazine and the like.

The trivalent organophosphorous compounds utilized in the novelcomposition of the present invention may be prepared in situ; forexample, a tertiary phosphine may be prepared from the correspondingphosphonium salt by the addition of a basic substance to a solution ofthe phosphonium salt.

The novel compositions of the present invention may be utilized withthose metals which are subject to tarnishing, that is those metals whichare capable of forming a surface film of contrasting color, formed on anexposed surface of a metal, and usually consisting of the oxide orsulfide of said metal. Illustrative of the metals which fall within thiscategory are such metals as copper, brass, aluminum, nickel, cobalt,silver, ferrous metal objects and the like.

A preferred embodiment of the novel metal cleaning and tarnishinhibiting composition of the present invention would, therefore,contain 10 percent by weight of tris(hydroxymethyl)phosphine, 1 percentby weight of octadecyl bis(hydroxymethyl)phosphine, and a sufficientUtilization of a primary phosphine in the novel composition of thepresent invention This example demonstrates the metal cleaning facilityof a primary phosphine with metallic silver.

A composition consisting of the following ingredients was prepared:

Percent by wt.

Stearyl cetyl ethoxylate 2.22 Methyl salicylate 1.11(3-hydroxypropy1)phosphine 11.11 Denatured alcohol 58.36

Water up to 100.

The stearyl cetyl ethoxylate was melted in a suitable container on asteam bath. The denatured alcohol and a small amount of water were thenadded to the melted stearyl cetyl ethoxylate with stirring until ahomogeneous mixture was obtained. The mixture was then cooled to roomtemperature, placed under a nitrogen blanket and the balance ofingredients were then added. The resulting solution was then admixedwith a halogenated hydrocarbon propellant, in the ratio of solution topropellant of 9:1. The halogenated hydrocarbon propellant consisted of amixture of dichlorodifluoromethane and dichlorotetrafluoroethane in theratio of 2:3 respectively.

Sterling silver strips measuring 4 by 2", and referred to as silvercoupons, were cleaned with a traditional silver cleaning composition andfinally rinsed to dryness in acetone. The coupons were placed in adesiccator and subjected to an atmosphere containing hydrogen sulfidefor 2 days, at which time the strips possessed a heavy coating oftarnish.

A silver strip prepared in the above manner was subjected to anapplication of the composition hereinabove prepared and a visualjudgment was made as to performance. The criteria of performance waswhether an appreciable brightness of the coupon would be observed in 30seconds of application. The aforementioned composition demonstratedeffective cleaning and satisfied the criteria of performance.

A metal cleaning composition incorporating a primary phosphine wasprepared in the manner hereinabove set forth, substituting for (3hydroxypropyl)phosphine, [2 (ethoxycarbonyl)ethyl]phosphine, thecomposition achieving the same effect as hereinabove demonstrated.

EXAMPLE II Utilization of a secondary phosphine in the novel compositionof the present invention This example demonstrates the metal cleaningfacility of a secondary phosphine with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example I:

Percent by wt. Stearyl cetyl ethoxylate 2.22Bis(3-hydroxypropyl)phosphine 10.5 Denatured alcohol 58.36 Water up to100.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criteria ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a seconddary phosphine wasprepared in the manner hereinabove set forth, substituting forbis(3-hydroxypropyl)phosphine, disodium bis(Z-carboxyethyl)phosphine,the composition achieving the same effect as hereinabove demonstrated.

EXAMPLE III Utilization of tertiary \phosphines in the novel compositionof the present invention Nonyl phenol ethoxylate 0.20Tris(hydroxymethyl)phosphine) 10.00 Hexylene glycol 5.00

Water up to 100.

The nonyl phenol ethoxylate and the hexylene glycol Were added to asmall amount of water, this mixture was then placed under a nitrogenblanket and the tris- (hydroxymethyl)phosphine and the remaining waterwere added. The resulting solution was then admixed with a halogenatedhydrocarbon propellant in the ratio of solution to propellant of 7:3.The halogenated hydrocarbon propellant consisted of a mixture ofdichlorodifiuoromethane and dichlorotetrafiuoroethane in the ratio of1:4, respectively.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criteria ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating tertiary phosphines waprepared in the manner hereinabove set forth, substituting fortris(hydroxymethyl)phosphine, tris- (3-hydroxypropyl)phosphine, thecomposition achieving the same effect as hereinabove demonstrated.

EXAMPLE IV Utilization of a phosphinite ester in the novel compositionof the present invention Percent by wt.

Dioctyl sodium sulfosuccinate 0.10 2-hydroxyethyl dipropylphosphinite15.00 Denatured alcohol 10.00

Water up to 100.

The dioctyl sodium sulfosuccinate and the Z-hydroxyethyldipropylphosphinite were added to the denatured alcohol under a nitrogenblanket. The water was then added to the above admixture. The resultingsolution was then admixed with an isobutane propellant in the ratio ofsolution to propellant of 4: 1.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phosphinite ester wasprepared in the manner hereinabove set forth, substituting forZ-hydroxyethyl dipropylphosphinite, ethyl dimethylphosphinothioite, thecomposition achieving the same effect as hereinabove demonstrated.

EXAMPLE V Utilization of a phosphinamide in the novel composition of thepresent invention This example demonstrates the metal cleaning facilityof a phosphinamide with metallic silver.

A composition consisting of the following ingredients was prepared:

Percent by wt. Octodecyl thioglycolate 0.50 Stearyl cetyl ethoxylate2.00 Methyl salicylate 0.50

N-Z-hydroxyethyl-p,p-diisobutylphosphinous amide 10.00 Denatured alcohol58.36 Water up to 100.

The stearyl cetyl ethoxylate was melted in a suitable container on asteam bath. The denatured alcohol, in which the octadecyl thioglycolatehad been dissolved, and a small amount of water were then added to themelted stearyl cetyl ethoxylate with stirring until a homogeneousmixture was obtained. The mixture was then cooled to room temperature,placed under a nitrogen blanket, and the balance of ingredients werethen added. The resulting solution was then admixed with a halogenatedhydrocarbon propellant, in the ratio of solution to propellant of 9:1.The halogenated hydrocarbon propellant consisted of a mixture ofdichlorodifiuoromethane and dichlorotetrafluoroethane in the ratio of2:3 respectively.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phosphinamide was preparedin the manner hereinabove set forth, substituting forN-Z-hydroxyethyhp,p-diisobutylphosphinous amide,p,p,-bis(2-hydroxyethyl)-N,N-dimethylphosphinous amide, the compositionachieving the same effect as hereinabove demonstrated.

EXAMPLE VI Utilization of a phosphonite ester in the novel compositionof the present invention This example demonstrates the metal cleaningfacility of a phosphonite ester with metallic silver.

A composition consisting of the following ingredients was prepared:

Percent by wt.-

Silicone oil 0.1 Dimethyl (3-hydroxypropyl) phosphonite 12.00 Denaturedalcohol 25.00

Water up to 100.

The silicone oil was added to the denatured alcohol, :and the resultingmixture was placed under a nitrogen blanket. Thedimethyl(3-hydroxypropyl)phosphonite was then added to the above mixturealong with the water. The resulting solution was then admixed with ahologenated hydrocarbon propellant, in the ratio of solution topropellant of 9:1. The halogenated hydrocarbon propellant consisted of amixture of dichlorodifluoromethane and dichlorotetralluoroethane in theratio of 2:3 respectively.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phosphinite ester wasprepared in the manner hereinabove set forth, substituting fordimethyl(3-hydroxypropyl)pl1osphonite, bis Z-hydroxyethyl) [2-ethoxycarbonyl ethyl] phosphonite, the composition achieving the sameeffect as hereinabove demonstrated.

EXAMPLE VII Utilization of a phosphonamide in the novel composition ofthe present invention This example demonstrates the metal cleaningfacility of a phosphonamide with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example I:

Percent by wt.

Stearyl cetyl ethoxylate 2.22

Methyl salicylate 0.50

P Isobutyl N,N,N',N' tetramethylphosphonous diamide 10.5

Denatured alcohol 58.36 Water up to 100.

EXAMPLE VIII Utilization of tertiary phosphite in the novel compositionof the present invention This example demonstrates the metal cleaningfacility of a tertiary phosphite with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example I:

Percent by wt.

Stearyl cetyl ethoxylate 2.22 Methyl salicylate 0.75 Triethylphosphite12.00 Denatured alcohol 58.36

Water up to 100.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a tertiary phosphite wasprepared in the manner hereinabove set forth, substituting fortriethylphosphite, trimethylphosphorotrithioite, the compositionachieving the same effect as hereinabove demonstrated.

9 EXAMPLE IX Utilization of a phosphorous triamide in the novelcomposition of the present invention This example demonstrates the metalcleaning facility of a phosphorous triamide with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example 1:

Percent by wt.

Stearyl cetyl ethoxylate 2.22 Methyl salicylate 1.11Hexamethylphosphorous triamide 11.11 Denatured alcohol 58.36

Water up to 100.

EXAMPLE X Utilization of a phosphinite ester amide in the novelcomposition of the present invention This example demonstrates the metalcleaning facility of a phosphinite amide with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example 1:

Percent by wt.

Stearyl cetyl ethoxylate 2.22 Methyl salicylate 0.5 EthylN-(2-hydroxyethyl)-p-methy1phosphonamidite l5 Denatured alcohol 60 Waterup to 100.

A silver strip, prepared in the manner set forth in EX- ample I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phosphinite ester amide wasprepared in the manner hereinabove set forth, substituting for ethylN-(Z-hydroxyethyl)-p-rnethylphosphonamidite, methyl p'ethyl N,Ndimethylphosphonamidothioite, the composition achieving the same effectas hereinabove demonstrated.

EXAMPLE XI Utilization of a phosphorous amide ester in the novelcomposition of the present invention This example demonstrates the metalcleaning facility of a phosphorous amide ester with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example I:

Percent by wt.

Stearyl cetyl ethoxylate 2 Methyl salicylate 0.25 Diethylmorpholinophosphonite Denatured alcohol 55 Water up to 100.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phos' phorous amide esterwas prepared in the manner hereinabove set forth, substituting fordiethyl morpholinophosphonite, dimethyl dirnethylphosphoramidodithioite,the composition achieving the same effect as hereinabove demonstrated.

EXAMPLE XII Utilization of a diphosphine in the novel composition of thepresent invention This example demonstrates the metal cleaning facilityof a diphosphine with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example I:

Percent by wt. Stearyl cetyl ethoxylate 3 Methyl salicylate 1.5Trimethylene bis[bis(hydroxymethyl)phosphine] 14 Denatured alcohol 60Water up to 100.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a diphosphine was prepared inthe manner hereinabove set forth, substituting for trimethylenebis[bis(hydroxymethyl) phosphine], tetrasodium ethylenebis[bis(carboxyethyl) phosphine], the composition achieving the sameeffect as hereinabove demonstrated.

EXAMPLE XIII Utilization of a phosphorous heterocycle in the novelcomposition of the present invention This example demonstrates the metalcleaning facility of a phosphorous heterocycle with metallic silver.

A composition consisting of the following ingredients was prepared inthe manner set forth in Example 1:

Percent by wt. Stearyl cetyl ethoxylate 2.5 Methyl salicylate 1.25Ethylene 2-hydroxyethyl phosphine 12 Denatured alcohol 50 Water up to100.

A silver strip, prepared in the manner set forth in Example I, wassubjected to an application of the composition hereinabove prepared anda visual judgment was made as to performance. The criterion ofperformance was whether an appreciable brightness of the coupon would beobserved in 30 seconds of application. The aforementioned compositiondemonstrated effective cleaning and satisfied the criterion ofperformance.

A metal cleaning composition incorporating a phosphorous heterocycle wasprepared in the manner hereinabove set forth, substituting for ethylene2-hydroxyethyl phosphite, 1-(hydroxymethyl)phosphorinane, thecomposition achieving the same effect as heerinabove demonstrated.

1 1 EXAMPLE xrv Illustration of the tarnish inhibiting effect of thenovel compositions of the present invention Tris(hydroxymethyDphosphine11.1 Octadecyl bis(hydroxymethyl)phosphine 1 Isopropanol 70 Water up to100.

The composition was prepared by simply dissolving thetris(hydroxymethy1)phosphine and the octadecylbis(hydroxymethyl)phosphine in the isopropanol under a nitrogen blanketand adding the remainder of water.

Each of the coupons were placed in the same desiccator and subjected toan atmosphere containing dydrogen sulfide, after 3 days the followingvisual observations were made. Sample A was heavily coated with tarnishand for the most part was substantially black in color. Sample B wastarnished, however, to a lesser degree than Sample A, and gave abrownish appearance. Sample C did not appear to have tarnishedappreciably and gave the appearance of having a slight yellow cast.

EXAMPLE XV In situ preparation of tris(hydroxymethyl)phosphine Thisexample demonstrates the in situ preparation oftris(hydroxymethyl)phosphine from its corresponding phosphonium salt.

A composition comprising the following ingredients was prepared:

Percent by wt. Tetrakis(hydroxymethyl)phosphonium chloride 48.8 Sodiummethoxide 10.8 Denatured alcohol up to 100.

The sodium methoxide was dissolved in a portion of the denaturedalcohol. The resulting solution. was placed under a nitrogen blanket andthe tetrakis(hydroxymethyl)phosphonium chloride was dissolved in theremaining alcohol with agitation. Upon the addition of thetetrakis(hydroxymethyl)phosphonium chloride solution there wasprecipitation of sodium chloride. The sodium chloride was then filteredleaving a solution of tris(hydroxymethyl)phosphine and formaldehyde indenatured alcohol. The resulting solution was then vacuum distilledremoving the denatured alcohol and the formaldehyde.

Although the invention has been described and illustrated by referenceto particular embodiments thereof, it will be understood that in itsbroadest aspects the invention is not limited to such embodiments, andthat variations and substitution of such equivalents may be resorted towithin the scope of the appended claims.

We claim:

1. The method of cleaning metal surfaces and imparting tarnishresistance thereto which comprises treating said surface with aneffective amount of an organic phosphine in water or a lower alkanol.

2. The method of claim 1 wherein the metal is copper or a copper alloy.

3. An article comprising a normally tarnishing metal surface havingapplied thereto as a tarnish inhibiting barrier in a carrier comprisingwater or a lower alcohol, a water or alcohol soluble oganic phosphine,said phosphine barrier being resistant to dissolution and removal uponcontact with water.

4. The article of claim 3 in which the metal is composed at least inpart of copper.

5. A metal cleaning and tarnish inhibiting composition comprising 0.1 to20% of an organic phosphine which is generally soluble in water or inalcohol of 1-5 carbon atoms; and a liquid carrier, comprising water or alower alkanol or mixtures thereof.

6. The composition of claim 5 wherein the liquid carrier containsdenatured alcohol.

7. The composition of claim 5 wherein the liquid carrier contains water.

8. The composition of claim 5 wherein the liquid carrier is isopropylalcohol.

9. A composition containing (a) at least 0.1% of an organic phosphinewhich is soluble in an alcohol of 15 carbon atoms or in water, (b) aliquid aqueous or alcoholic carrier, and (c) an antioxidant whichstabilizes said organic phosphine against oxidative deterioration; saidcomposition being capable of forming a tarnish protective barrier whenapplied to a normally tarnishing metal.

10. A composition suitable for application to a metal surface from apropellant container and capable of applying a tarnish protectivebarrier to said metal surface, comprising (a) at least 0.1% of anorganic phosphine which is soluble in water or an alcohol of 1-5 carbonatoms, (b) an aqueous or alcoholic solvent for said phosphine, and (c)an inert halogenated hydrocarbon propellant wherein the ratio of (a)plus (b) to propellant is 7:3 to 9:1.

References Cited UNITED STATES PATENTS 3,079,311 2/ 19'63 Hettinger260606.5 3,118,951 l/l964 Burg et al. 252606.5 3,137,692 6/1964 Maier260400 3,251,883 5/1966 Rauhut et a1. 260-606.5 3,257,460 6/ 1966 Gordanet a1 260606.5

LEON D. ROSOL, Primary Examiner.

W. E. SCI-IULZ, Assistant Examiner.

